I hate to make the obvious jokes, so I’ll simply say I was on this week’s Skeptic’s Guide to the Universe talking about methane on Mars and the tilt of Uranus. I’m glad they invited me on; I hadn’t heard of either of these stories until Steve Novella alerted me to them before we did the interview.

Basically, a new hypothesis has come out that the large tilt of Uranus (98°) is not from a collision, but instead had its natural tilt reinforced by a large moon that has since been ejected. Also, scientists tested the idea that the methane seen to change on Mars with the seasons might be from meteorites, and find that they don’t supply nearly enough to explain the observations. We also talk JREF, solar power, the Norway lights, and the usual nonsense. I just finished listening to the whole episode, and thought it was pretty good despite me being on it, so go give it a listen!

Comments (25)

Since you asked for it…
You obviously have not spent a day with me… that would erase all skepticism about Methane and Uranus… or should that be Myanu… Ohhh, family blog… never mind… You get the smell… err, I mean drift…

I did see that article about the Martian Methane a couple of days ago. I believe that since they have ruled out meteorites, the only 2 possibilities left were Volcanism (highly unlikely), or biological (most likely).

I would think that mission planners at NASA would be all over this, and petition Congress for funding for a Life Science Mission to Mars. There has even been renewed speculation concerning the Meteorite from Antarctica, that contains what appear to be fossilized microbial life, and that, indeed, it may be microbial in origin after all. There has always been controversy over the results from the Viking probe. See link:

I simply cannot understand why this type of mission is not thrust to the forefront. The recent Spirit and Opportunity missions, as well as the Phoenix Lander have given us amazing results, but I think it is time we answered the more important question: Is there now life on Mars? The new findings concerning Methane are definitely pointing in that direction.

I suppose the next question, if life is confirmed, is what would that mean for manned missions to Mars? Should this lead to some type of quarantine for Mars? After all, if we don’t know the nature of these microbes, I would hate to think of what may happen if we accidentally brought them home!

I don’t think the two remaining possibilities for methane on Mars were volcanism and life. They’ve ruled out volcanism, due to there not being any currently active volcanoes on Mars. The non-life hypothesis was that the methane was being released from methane ice in a reaction between volcanic rock and water.

The life hypothesis seems like the most likely possibility at this point, but I’m trying not to get too excited about it!

A little bit of caution with uncertain extraordinary claims is warranted, particularly in the political arena. If you sell your position too much to get funding, and then turn out to be wrong, even just perceived to have been wrong, your risk blowing your credibility for getting any more funding in the future.

I don’t think we can reasonably plan a Life Science mission to Mars until we get a better handle on where, precisely to look. If life is ubiquitous on Mars, as it is on earth, then plopping a probe down anywhere would give us a reasonable chance for success, but even on a planet like Earth, if you dropped a probe somewhere into the most common/largest/dominant habitat on the planet, the Abyssal Plain of the ocean floor, you would find the density of life there quite low, and if your instruments were crude, or looking for the wrong kind of life, you might even miss it entirely.

And if life on Mars is not ubiquitous, but rare, limited to special sheltered environments, without first knowing what those environments are likely to be, and having at least some theoretical inkling of the the type of life and its likely properties that might inhabit such environments, one could stumble around forever, searching blindly, and not find anything. This might well have been one of the pitfalls that thwarted the Viking experiments.

Thanks for post. You answered clearly some of the questions I had myself. Maybe life might be on the walls of caves up on steep hills. In which case we may need to develop flying and/or floating probes. Some sort of helicopter like probe that given the radio lag between Earth and Mars would need to be able to navigate on its own and identify caves.

I always thought 90 degrees forms a right angle to the plane of the ecliptic. Thus, if Uranus is tilted 98 degrees, it’s also 8 degrees off the plane of the ecliptic with the north pole pointing 8 degrees south. Or, in other words, the north pole is actually a south pole(because it’s pointing south of the solar plane of the ecliptic.

I assume they define the N-S axis so that the rotation fits the revolution around the Sun. Thus, while Venus can be said to orbit ‘backwards’, it is in reality going the right way round, just upside down.

Well it turns out that there are multiple ways to define North. You can either define it via the sense of rotation (i.e. if you look down on the North pole you see the planet rotate anticlockwise). This keeps the mathematics simple.

The IAU on the other hand define North according to which pole points above the ecliptic plane. Since often the observations lead to a degeneracy between which direction the planet is rotating, the IAU definition keeps things consistent, most of the time. I believe a couple of asteroids have been discovered which precess so that the poles alternate above and below the ecliptic plane.

I’ve used Solar north as my reference for the ecliptic, which is consistent with IT’S anti-clockwise rotation. Just wondering how we can refer to a north polar tilt of 98 degrees, when 90 degrees would have its poles pointing directly at the solar equator. Another 8 degrees,,, ah, I see. Never mind. It’s the anti-clockwise of the planet that defines its north pole.

Gary Ansorge: Yeah, Uranus is technically listed as having retrograde rotation, which can be defined as an axial tilt greater than 90 degrees. Therefore, saying that Uranus’ north pole points south is technically correct (the very best kind of correct) — but the truth is that Uranus’ poles point “sideways.”

Venus, which is truly retrograde, has a tilt of something approaching 180 degrees. And 180 degrees is the highest axial tilt can go (i.e. a tilt of 270 degrees is indistinguishable from a tilt of 90 degrees).

Michael L: As for why the possibility of life on Mars doesn’t fire the popular (and political) imagination…that’s because most people think life has already been discovered on Mars. They’ve seen it on tv and in movies many times, so it must be true.

It’s long been an article of faith in the scientific community that the discovery of extraterrestrial life will be a momentous event, a game-changer, a massive shock to the psyche of human beings worldwide. I maintain that the news will be met with yawns or, at most, polite curiosity. Because the public already believes extraterrestrial life exists.

We almost always underestimate the level of scientific illiteracy among the general populace.

“Like the Moon, volcanism on Mars is very old. …. The youngest lava flows on Olympus Mons are only 20 to 200 million years old. These flows are very small, however, and they probably represent the last gasp of martian volcanism. Thus, the odds of finding an active volcano on Mars today are very small.”

The non-life hypothesis was that the methane was being released from methane ice in a reaction between volcanic rock and water.

The life hypothesis seems like the most likely possibility at this point,

How come life is most likely? Clathrates and methane emissions are ubiquitous, see Earth and Titan. While life is rare for all we know.

Actually I would argue that methane as a sign for life is a very long shot, for what we know from life here.

Methanogens on Earth only appeared once. They also use a metabolism that originated in aerobic metabolisms, AFAIU the biologists. That is, it is rare, and we would only expect to see it on planets that were once oxygenated. The later takes time, biomass and access to light, the later two something that we don’t expect much of in Mars putative buried biosphere.

In fact, it can be worse. Methanogens are the more derived archaebacteria. Moreover, apparently late ancestry for archaeabacteria isn’t the main stream hypothesis among biologists, but truth is there isn’t any distinguishing fossil evidence for archaebacteria (or eukaryotes) beyond ~ 0.8 Ga or so AFAIU. While there is plenty of evidence for bacteria specifically, in the form of cyanobacteria.

Nor are there any reliable phylogenetic evidence for archaeabacteria being, um, archaic. Molecular clocks for specific genes are unreliable over eons, and the massive gene comparison I know of places archaeabacteria as sisters or at the most immediate relatives to eukaryotes. This former is, for plenty of other reasons including several morphological (for example membranes and protein transport mechanisms), the phylogeny that biologist Cavalier-Smith proposes in his neomura theory.

If archaebacteria are latecomers as us (and all evidence what I know of points to that, including the seemingly derived robustness of archaeabacteria extremophiles) methane producing metabolism is the latest and so most unlikely metabolism to appear, based on what we observe.

Ah, the great power of the skeptic: let’s all hear a big HUZZAH for James Randi, who’s now firmly in the camp of the anthropogenic global warming deniers. How long until we hear the BA comment on this? (or how long until this post sees the light of photons? I expect the answer is the same…..). For an INFORMED take on this that I happen to agree with totally, skip on over to a fellow blogger of the ba, Sean Carroll, at cosmicvariance.

OOps, not at all sorry for the above post, but my apologies for putting it in the wrong place and not seeing the RIGHT place. Still, the BA’s response (kudos for giving one!) is weak compared to that of Sean Carroll.

The enzymes that methanogens use to make methane prefer lighter isotopes so there is a biological signature that is unequivocal, at least here on earth. Would that not be the case on Mars? What better mission than a few mass spec’s plonked down at the sources of the methane plumes? If martian methane is light, we have some hard evidence for life.

Basically, a new hypothesis has come out that the large tilt of Uranus (98°) is not from a collision, but instead had its natural tilt reinforced by a large moon that has since been ejected.

The proper name for Uranus should really be Ouranos – the Greek spelling of the original greek god rather than the wrongly transliterated Roman spelling. I’m not the only one who thinks this either there’s even a facebook group (of which I’m a member but not the founding one) dedicated to this. See : http://www.facebook.com/group.php?gid=189939051777

As they put it on the home page there :

*** “All the planets except one are named after Roman gods, and Ouranos is the one exception. Unfortunately it has become the brunt of joke after joke due to a Latinization of the original Greek name, Ouranos. We do not call Poseidon Posidon, so why make Ouranos the exception? Ouranos is a magnificent planet that has been subject to a bromidic and stale joke for far too long.”

***

As for the sideways position of Ouranos being due to ejecting a large moon, all I can say is ejected *how*?

Test. test. Why is my regular user name seemingly blocked? What did I do? Or something really weird is going on. Sometimes I see people refer to a post #, but the actual post is a couple numbers away.

My sympathies, I had something like that happen not so long ago to me so I know how frustrating it can be.* I hope it gets sorted out for you.

As for the post numbers, it seems they don’t take posts “awaiting moderation” into account and so
these come in “out of sequence” later & mess up the numbering. I don’t know if the BA can change the system so that “awaiting mods” posts come in with the number at which they appear or something like that? I’d love to see something like this done as it does create potential confusion when the numbering changes as it does now.

PS. Please BA can you write a blog post about the recent discovery of the “waterworld” super-Earth / gas dwarf GJ1214?

I kind of wondered about that myself after reading it again. I thought, “”If Mars has been volcanically dead for millions of years, how could there be some type of reaction taking place today. I’m not sure geologic processes take place when volcanic rock reacts with water, though. (And, where is there that much water on Mars? I know it would have to be very deep under the surface.)

Regarding geological processes on Mars, even if the planet has cooled down sufficiently that it can’t punch magma through the crust to the surface, it doesn’t mean that less energetic systems aren’t still active.

As for Uranus vs Ouranos (which would I’m sure end up getting pronounced as “our anus” and thus not avoiding any tedious and juvenile humour at all), quite a lot of Greek words have come to the English language via Latin, this is expected. If you wanted to use the closest Latin equivalent, you’d probably have to go with Caelus.

Huh? Where does the C come from? C is a perfectly respectable letter in Latin! None of this messing around with suspicious letters like K which is only good when you have to steal a word from Greek! And don’t get me started on Y…